The most widely deployed "home server", FreeNAS, is historically based on NAS/LAN protocols. Most home users want to share file storage across multiple devices, which historically has been SMB/NFS/DLNA. Over time, NAS devices have added cloud/WAN protocols, like WebDAV, S3, etc.
The most expensive aspect of server software development is data integrity/availability, e.g. ZFS or other high-integrity filesystem. Services atop the storage layer are usually built by different teams, often from different eras.
"home server" here was intended to mean "network-facing http and maybe smtp server", not "server for domestic duties". Sorry if that wasn't more clear.
of course, no reason why the same box couldn't do both.
The most expensive aspect of server software development is data integrity/availability, e.g. ZFS or other high-integrity filesystem. Services atop the storage layer are usually built by different teams, often from different eras.